Synthesis of Highly Heterocyclic Fluorescent Molecules: 2-imino-2H-pyrano[3,2-c] Pyridin-5(6H)-ones Derivatives.

New highly fluorescent 2-imino-2H-pyrano[3,2-c]pyridin-5(6H)-onesderivatives were synthesized using a simple route. The present molecules were prepared by two methods with good yield. The structures were characterized by NMR1H, 13 C, and elemental analysis. Also, the effect of solvent and concentration on the fluorescence properties were demonstrated. However, the high fluorescence intensity in the range of 70,000-75,000 a. u. was obtained with a concentration equal to 10- 6 M of prepared molecules. The intensity was influenced also by the molecule structure and solvent.

Biofouling of reverse osmosis membranes: assessment by surface-enhanced Raman spectroscopy and microscopic imaging.

The decline in the performance of spiral-wound reverse osmosis (SWRO) membranes is frequently due to biofouling. This study focus on qualitative and quantitative diagnosis of SWRO membrane biofouling. Bacterial counts on the different surfaces of the fouled membranes were carried out. Surface enhanced Raman spectroscopy (SERS) was performed to highlight clogging materials as well as their natures and identity. The topography of the fouled membranes and the structures of biofilms were visualized by fluorescence microscopy (FM) and scanning electron microscopy (SEM). The results indicated the presence of bacteria in the different SWRO membrane areas. Those strongly adhered were significantly higher than those weakly. It varied between 26 × 105 and 262 × 105 CFU m-2. However, SERS mapping showed different fouling levels and the thickness of the fouling layer was 5 µm. Microscopic imaging revealed biotic and abiotic deposits. These data can together allow better management of the seawater desalination process.

Efficient Synthesis of 2-Aminopyridine Derivatives: Antibacterial Activity Assessment and Molecular Docking Studies.

A new and suitable multicomponent one-pot reaction was developed for the synthesis of 2-amino-3-cyanopyridine derivatives. BACKGROUND: This synthesis was demonstrated by the efficient and easy access to a variety of substituted 2-aminopyridines using enaminones as key precursors under solvent-free conditions. METHODS: A range of spectroscopic techniques was used to determine and confirm the chemical structures (FTIR, 1H NMR, 13C NMR). The antimicrobial potency of synthesized compounds (2a-d) was tested using disk diffusion assays, and the Minimum Inhibitory Concentration (MIC) for the active compounds was determined against a panel of microorganisms, including Gram-positive and Gram-negative bacteria and yeasts. Moreover, a docking analysis was conducted by Molecular Operating Environment (MOE) software to provide supplementary information about the potential, as well as an ADME-T prediction to describe the pharmacokinetic properties of the best compound and its toxicity. RESULTS: The results of the antimicrobial activity indicated that compound 2c showed the highest activity against Gram-positive bacteria, particularly S. aureus and B. subtilis whose MIC values were 0.039 ± 0.000 µg·mL-1. The results of the theoretical study of compound 2c were in line with the experimental data and exhibited excellent antibacterial potential. CONCLUSIONS: On the basis of the obtained results, compound 2c can be used as an antibacterial agent model with high antibacterial potency.

Hemisynthesis of coumarin derivatives from Ammodaucus leucotrichus oil extract: organobase-catalyzed reaction, analytical study by diffusion-ordered spectroscopy NMR and differential scanning calorimetry.

This paper presents an in-depth chemical and analytical study of a natural substance extracted from Ammodaucus leucotrichus Coss. & Dur and its derivatives after hemisynthesis. The analysis was performed using Diffusion-Ordered Spectroscopy (NMR DOSY) and Differential Scanning Calorimetry (DSC) as general methods. The results show an interesting chemical reactivity towards coumarin-derived bisnucleophiles (4-hydroxycoumarin and triacetic acid lactone), and products obtained by hemisynthesis of pyrano[4,3-b]pyrane derivatives following Knoevenagel condensation and Michael's addition on this natural substance with the use of 4-pyrolidinopyridine organobase as catalyst.

New antibacterial cadiolide analogues active against antibiotic-resistant strains.

The synthesis of new cadiolide analogues was carried out using a one-pot multi component synthesis. The antibacterial activity of these molecules was evaluated on standard and antibiotic resistant bacterial strains chosen for their involvement in human health or in food-born poisoning. Four molecules have shown good activities with MICs of 2 µg/mL-1. The introduction of an indole group or the conversion of the lactone into lactam have highlighted two new families of molecules with promising antibacterial activity. In addition, most of these active molecules are devoid of cytotoxic activity against keratinocyte cells.

Structural characterization, antioxidant, and antibiofilm activities of Coffea canephora green seeds.

OBJECTIVES: In order to explore Coffea canephora green seeds as natural extract for application in the functional-food industry, we focused this study to the evaluation of the antioxidant and the antiadhesion effect of C. canephora green seeds extracts. METHODS: The analysis of C. canephora green seeds extracts was carried out by RP-HPLC-PDA. These extracts were screened for antioxidant activities by ABTS and phenanthroline assays. The antibacterial activity was determined by microdilution method against three reference bacteria. The inhibition of bacterial adhesion at 1/8 MIC was carried out against three reference bacteria. RESULTS: The RP-HPLC-PDA revealed the presence of gallic acid, vanillin, quercetin, chlorogenic acid, and P-coumaric acid. The n-buatnol extract have the highest activity ABTS assays (3.96 ± 0.08 µg/mL). For this extract, the A0.5 was 1.90 ± 0.05 µg/mL for phenanthroline assay. The n-butanol extract and the methanolic extract have the higher antibacterial activity against Staphylococcus aureus ATCC 25923 (40 µg/mL).At MIC/8, the extracts of C. canephora showed 70% higher antidhesive activity against S. aureus ATCC 25923. CONCLUSIONS: Our finding provides an effective and specific new approach to the search of antioxidant and antiadhesive compounds for different uses.

Antifungal activity of the Algerian Lawsonia inermis (henna).

CONTEXT: Lawsonia inermis Linn. (Lythraceae) or henna has been used since the earliest times as a medicine, preservative, and cosmetic. It has long been recommended in traditional medicine as an astringent, purgative, and abortifacient. OBJECTIVE: Lawsone and six extracts of L. inermis plant, used by Algerian traditional healers to treat infectious diseases, were screened for their antifungal activity against filamentous fungi. MATERIALS AND METHODS: Water and five organic extracts - DMSO, ethanol, chloroform, ethyl acetate, and di-ethyl ether - of L. inermis leaves, collected in the area of Adrar (Algeria), were prepared by soaking 25 g of powdered plant in 100 mL of solvent. The extracts were screened for antifungal activity using the poisoned food technique against five filamentous fungi. RESULTS: Results demonstrated that the best yield (8.03%) was obtained with the ethanol extract. The commercial lawsone showed potentially interesting MICs against the strains Fusarium oxysporum (12 µg/mL) and Aspergillus flavus (50 µg/mL). The ethanol extract showed the only interesting MIC (230 µg/mL of crude extract) against the strain F. oxysporum compared with other extracts. DISCUSSION AND CONCLUSION: These results suggest that the Algerian L. inermis plant has antifungal activity that can be related to the presence of lawsone in the leaves plant. The results can be exploited largely in research of new antifungal drugs.